The fortress of Langeais is on the Loire River and has had a very warlike history.  It’s really two castles as the first is now a park and had been pretty much destroyed by all the medieval warfare. The chateau’s website is really good: <http://chateau-de-langeais.com/en/>.  You can look at the photos at the site and even read a summarized pictorial history of the place.  Beautiful views of the surrounding area are had here, including a really neat medieval style modern bridge.